Labor unions have been in steep decline in recent years as right-to-work states like South Carolina continue to attract large companies, both foreign and domestic.

Thirty-thousand labor union employees at Boeing would be affected should Boeing decide to move its new 777X project out of Washington, according to an Associated Press report. For its part, Boeing will weigh a state-legislature approved package of incentives worth about $8.7 billion and a “promise” of another $10 billion in infrastructure improvements against union demands.

About 67% of IAM members voted to kill the contract proposal that included cutbacks in corporate pension contributions, smaller wage increases and reduced healthcare benefits. The International Association of Machinists and Aerospace Workers (IAM) leadership negotiated the new contract with Boeing that would have taken effect in 2016, and the agreement was shot down by local unions at the Boeing plant.

The local union president told members they had "preserved something sacred by rejecting the Boeing proposal. We've held on to our pensions and that's big. At a time when financial planners are talking about a 'retirement crisis' in America, we have preserved a tool that will help our members retire with more comfort and dignity."

It is not clear how union leaders will respond if Boeing decides to move the 777X project out of state. Boeing recently defied Washington union leaders by building a plant in South Carolina to manufacture the 787 Dreamliner. Workers are not forced to belong to unions and pay dues in South Carolina, a right-to-work state.